A little defensive there. I'm just trying to help. Sounds like you have already decided and I have given you the answer you didn't want to hear. lol
There is what you should do, and what you could do.
There is a difference between "influenced by" and "using bits from" or "directly lifting". I don't know about shakermaker in particular, or any deals done behind the scenes, I don't know if they got permission or not, or settled it in court later. Do you know? If it was that obvious I am sure Coca Cola will have been paid at some point.
Pop music is littered with songs where artists didn't get permission but instead went ahead and released a song. And then got sued.And lost.
As a non-commercial release, could you get away with doing a cover? Possibly, but you better be absolutely sure there are no commercial elements (even YouTube advertising, google asense etc.) and that you are prepared to be sued whether it is a commercial release or not. While many labels and publishers will look leniently on non-commercial covers, not all will. Pretty well none will look favourably on a strongly similar song presenting itself as an original, that is considered plagiarism and generally slammed, commercial or not.
From the level of detail you know about the remix tracker's permissions I am guessing you have asked him?
Just because this tracker hasn't been sued doesn't mean he won't be.
The point is, why would you not ask permission? It's easy enough to do.
If you are doing a commercial release it is better to be completely up front.
If you are doing a non-commercial release most are quite accommodating.
- the original is a pop song (from a permissions perspective it is completely irrelevent)
- the remix is a tracker tune made purely on a computer. It doesn't contain any actual samples from the orignal. (are you?)
- the melody, chords, and beat are similar or very similar, but still distinct. (How distinct? There is a measureable formula, plus it comes down to a jury. Additionally chords and beat don't count from a song copyright perspective, though they can count from an arrangement perspective. From a song perspective, the melody and lyrics are the important part.)
- the original has lyrics, the remix doesn't. (does yours, are they the same/similar?)
- the use of remix would be as background music to a computer game. This is a distinctly different use from what the original music was made for. (doesn't matter from a permission perspective)
- the computer game is a small scale commericial release (Ahhhhhh! The scale doesn't matter. If the publisher finds out and consider it to be very similar... they could sue you. So much so that it takes your game off the shelves, and they could claw back moneys, whether you made a profit or not. beacause any publisher will want a share of a commercial release of ANY kind if THEY consider YOUR song is similar.)
Going by the last bit, you better be very sure that your song is measurably different. In a legal sense. Additionally, if I were you I would be wanting written permission from the tracker if what you do is borrowing in any way from his work. Otherwise he could be flat broke and aware that your game has become very successful, or your software company has, even years later, and then he could think.... why not and engage a lawyer. It has happened many times in the pop industry and in the gaming and other industries. Same goes for publishers, labels and artists. ie they can decide at any point if they discover it and deem it to be similar enough.... hence me saying you better be very sure of how similar it is legally.
Even tough you haven't named the track, I doubt it would be too hard for them to prove that you have had exposure to the track or remix.
I am not trying to be a pain in the ass, or rain on your parade. I am trying to help. You asked a question and I answered with what I consider to be the correct answer. I am not a lawyer. My answer is not definitive.
If you are serious, consult an entertainments lawyer.